A milling machine of this type is known, in which the broach presents a vertical axis and moves horizontally. The cylindrical mill is disposed on the side of the broach head remote from the horizontal guiding slideways with which the fixed standard is provided. This latter is fixed on a concrete mass of large dimensions of which a part, which extends below and in front of the broach head, serves as support for the pieces to be machined, the latter being held by fixation means fast with the concrete frame.
Although these milling machines are very heavy, they lack rigidity, as they present considerable overhangs between, on the one hand, the foot of the fixed standard and the piece to be machined and, on the other hand, between the foot of the fixed standard and the mill. Deformations occur due to the torsion and bending, during machining of the workpiece, further to these considerable overhangs. This brings about variations in the distance existing between the piece to be machined and the mill.
A machine incorporating a horizontal broach and a mobile standard is also known, employing a mill with a surface of large diameter. The piece to be machined is also fixed on the concrete mass during machining, which brings about considerable overhangs.
The same applies for a third type of machine incorporating a vertical broach and mobile standard which employs a so-called rolling cylindrical mill.
It is an object of the present invention to propose a machine of the type mentioned, which considerably reduces the variations in distance between the piece to be machined and the mill, and which makes it possible to obtain a continuous cut without vibrations, which leads to an increased life of the tools.